I do like several others have mentioned - go to the right of the left turn lane just in front of the first car. In my experience if I'm there first (and on the right) the first car usually stops to the left and just behind me - I'm sure so they can keep an eye on me. I can turn left without slowing any of the cars down by keeping to the outside of the turn. And nobody has to get around me again as I ride on roads with shoulders.